brake question Kodiak

Hi I just bought a 1982 366 powered medium duty dump C7000{theres no badges so I asuume its a C7000). The dash says Kodiak. Brought it in for rear brake service..the pads were fine but they were airbound even after bleeding..I told them the adjusters needed looking at..After 4 days and the promise to have it back by today they call me at 5 o'clock on Friday. Besides the cylinders and seals the adjusters on the backplate need to be replaced..200 each and 2 per wheel..800 for adjusters sounds crazy..Is anyone familiar with the setup on theses trucks? The cylinder part number is FD-24491 Wagner Lockheed. I dont have the adjuster part number but would sure like to find it..They sent it out to be matched..I know they are riveted to the backplate and the replacements bolt on..If anyone has that part number and a picture I'd really appreciate it..Have to know how bad I'm being gouged before we have at it on Monday..thanks